/*
* Entagged Audio Tag library
* Copyright (c) 2003-2005 Rapha�l Slinckx <raphael@slinckx.net>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package entagged.audioformats.generic;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import entagged.audioformats.AudioFile;
import entagged.audioformats.Tag;
import entagged.audioformats.EncodingInfo;
import entagged.audioformats.exceptions.CannotReadException;
/*
* This abstract class is the skeleton for tag readers. It handles the creation/closing of
* the randomaccessfile objects and then call the subclass method getEncodingInfo and getTag.
* These two method have to be implemented in te subclass.
*
*@author Raphael Slinckx
*@version $Id: AudioFileReader.java,v 1.1 2007/03/23 14:17:15 nicov1 Exp $
*@since v0.02
*/
public abstract class AudioFileReader {
/*
* Returns the encoding info object associated wih the current File.
* The subclass can assume the RAF pointer is at the first byte of the file.
* The RandomAccessFile must be kept open after this function, but can point
* at any offset in the file.
*
* @param raf The RandomAccessFile associtaed with the current file
* @exception IOException is thrown when the RandomAccessFile operations throw it (you should never throw them manually)
* @exception CannotReadException when an error occured during the parsing of the encoding infos
*/
protected abstract EncodingInfo getEncodingInfo( RandomAccessFile raf ) throws CannotReadException, IOException;
/*
* Same as above but returns the Tag contained in the file, or a new one.
*
* @param raf The RandomAccessFile associted with the current file
* @exception IOException is thrown when the RandomAccessFile operations throw it (you should never throw them manually)
* @exception CannotReadException when an error occured during the parsing of the tag
*/
protected abstract Tag getTag( RandomAccessFile raf ) throws CannotReadException, IOException;
/*
* Reads the given file, and return an AudioFile object containing the Tag
* and the encoding infos present in the file. If the file has no tag, an
* empty one is returned. If the encodinginfo is not valid , an error is thrown.
*
* @param f The file to read
* @exception CannotReadException If anything went bad during the read of this file
*/
public AudioFile read(File f) throws CannotReadException {
if (!f.canRead())
throw new CannotReadException("Can't read file \""+f.getAbsolutePath()+"\"");
if(f.length() <= 150)
throw new CannotReadException("Less than 150 byte \""+f.getAbsolutePath()+"\"");
RandomAccessFile raf = null;
try{
raf = new RandomAccessFile( f, "r" );
raf.seek( 0 );
EncodingInfo info = getEncodingInfo(raf);
Tag tag;
try {
raf.seek( 0 );
tag = getTag(raf);
} catch (CannotReadException e) {
System.err.println(e.getMessage());
tag = new GenericTag();
}
return new AudioFile(f, info, tag);
} catch ( Exception e ) {
throw new CannotReadException("\""+f+"\" :"+e,e);
}
finally {
try{
if(raf != null)
raf.close();
}catch(Exception ex){
System.err.println("\""+f+"\" :"+ex);
}
}
}
}